Table 3.

Test–Retest and Absolute Reliability of Outcome Measures

Measure	ICC	95% CI	SEM*	SEM 95% CI**	MDC95***
TUG (s)	0.69	0.41, 0.85	1.75	3.43	4.85
NUDS	0.56	0.21, 0.78	1.94	3.80	5.38
S&E	0.70	0.43, 0.86	4.45	8.72	12.33
ABC	0.79	0.57, 0.90	4.01	7.86	11.12
PDQ-8	0.82	0.63, 0.91	1.96	3.84	5.43
SSE	0.72	0.44, 0.87	0.81	1.59	2.25

^*SEM=SD of the difference scores divided by √2

^**SEM 95% CI was calculated as follows: SEM×1.96

^***MDC₉₅=SEM×√2×1.96

TUG=Timed up-and-go test; NUDS=Northwestern University Disability Scale; S&E=Schwab & England Activities of Daily Living Scale; ABC=Activities-specific Balance Confidence Scale; PDQ-8=Parkinson's Disease Questionnaire—Short Form; SSE=Stanford Self-Efficacy for Managing Chronic Disease 6-Item Scale; ICC[3,1]=intra-class correlation coefficient; SEM=standard error of measurement